use rustc::hir::*;
use rustc::lint::*;
-use rustc::middle::const_val::ConstVal;
use rustc::ty::{self, Ty};
-use rustc::ty::subst::Substs;
-use rustc_const_eval::ConstContext;
-use rustc_const_math::ConstInt;
use std::cmp::Ordering;
use std::collections::Bound;
use syntax::ast::LitKind;
-use syntax::ast::NodeId;
use syntax::codemap::Span;
-use utils::paths;
-use utils::{expr_block, in_external_macro, is_allowed, is_expn_of, match_type, remove_blocks, snippet,
- span_lint_and_sugg, span_lint_and_then, span_note_and_lint, walk_ptrs_ty};
-use utils::sugg::Sugg;
+use crate::utils::paths;
+use crate::utils::{expr_block, in_external_macro, is_allowed, is_expn_of, match_qpath, match_type, multispan_sugg,
+ remove_blocks, snippet, span_lint_and_sugg, span_lint_and_then, span_note_and_lint, walk_ptrs_ty};
+use crate::utils::sugg::Sugg;
+use crate::consts::{constant, Constant};
/// **What it does:** Checks for matches with a single arm where an `if let`
/// will usually suffice.
/// _ => ()
/// }
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub SINGLE_MATCH,
- Warn,
+ style,
"a match statement with a single nontrivial arm (i.e. where the other arm \
is `_ => {}`) instead of `if let`"
}
/// _ => bar(other_ref),
/// }
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub SINGLE_MATCH_ELSE,
- Allow,
+ pedantic,
"a match statement with a two arms where the second arm's pattern is a wildcard \
instead of `if let`"
}
/// _ => frob(&x),
/// }
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub MATCH_REF_PATS,
- Warn,
+ style,
"a match or `if let` with all arms prefixed with `&` instead of deref-ing the match expression"
}
/// false => bar(),
/// }
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub MATCH_BOOL,
- Warn,
+ style,
"a match on a boolean expression instead of an `if..else` block"
}
/// _ => (),
/// }
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub MATCH_OVERLAPPING_ARM,
- Warn,
+ style,
"a match with overlapping arms"
}
/// Err(_) => panic!("err"),
/// }
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub MATCH_WILD_ERR_ARM,
- Warn,
+ style,
"a match with `Err(_)` arm and take drastic actions"
}
+/// **What it does:** Checks for match which is used to add a reference to an
+/// `Option` value.
+///
+/// **Why is this bad?** Using `as_ref()` or `as_mut()` instead is shorter.
+///
+/// **Known problems:** None.
+///
+/// **Example:**
+/// ```rust
+/// let x: Option<()> = None;
+/// let r: Option<&()> = match x {
+/// None => None,
+/// Some(ref v) => Some(v),
+/// };
+/// ```
+declare_clippy_lint! {
+ pub MATCH_AS_REF,
+ complexity,
+ "a match on an Option value instead of using `as_ref()` or `as_mut`"
+}
+
#[allow(missing_copy_implementations)]
pub struct MatchPass;
MATCH_BOOL,
SINGLE_MATCH_ELSE,
MATCH_OVERLAPPING_ARM,
- MATCH_WILD_ERR_ARM
+ MATCH_WILD_ERR_ARM,
+ MATCH_AS_REF
)
}
}
check_match_bool(cx, ex, arms, expr);
check_overlapping_arms(cx, ex, arms);
check_wild_err_arm(cx, ex, arms);
+ check_match_as_ref(cx, ex, arms, expr);
}
- if let ExprMatch(ref ex, ref arms, source) = expr.node {
- check_match_ref_pats(cx, ex, arms, source, expr);
+ if let ExprMatch(ref ex, ref arms, _) = expr.node {
+ check_match_ref_pats(cx, ex, arms, expr);
}
}
}
let els = remove_blocks(&arms[1].body);
let els = if is_unit_expr(els) {
None
- } else if let ExprBlock(_) = els.node {
+ } else if let ExprBlock(_, _) = els.node {
// matches with blocks that contain statements are prettier as `if let + else`
Some(els)
} else {
fn check_overlapping_arms<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ex: &'tcx Expr, arms: &'tcx [Arm]) {
if arms.len() >= 2 && cx.tables.expr_ty(ex).is_integral() {
- let ranges = all_ranges(cx, arms, ex.id);
+ let ranges = all_ranges(cx, arms);
let type_ranges = type_ranges(&ranges);
if !type_ranges.is_empty() {
if let Some((start, end)) = overlapping(&type_ranges) {
if_chain! {
if path_str == "Err";
if inner.iter().any(|pat| pat.node == PatKind::Wild);
- if let ExprBlock(ref block) = arm.body.node;
+ if let ExprBlock(ref block, _) = arm.body.node;
if is_panic_block(block);
then {
// `Err(_)` arm with `panic!` found
}
}
-fn check_match_ref_pats(cx: &LateContext, ex: &Expr, arms: &[Arm], source: MatchSource, expr: &Expr) {
+fn check_match_ref_pats(cx: &LateContext, ex: &Expr, arms: &[Arm], expr: &Expr) {
if has_only_ref_pats(arms) {
- if let ExprAddrOf(Mutability::MutImmutable, ref inner) = ex.node {
- span_lint_and_then(
- cx,
- MATCH_REF_PATS,
- expr.span,
+ let mut suggs = Vec::new();
+ let (title, msg) = if let ExprAddrOf(Mutability::MutImmutable, ref inner) = ex.node {
+ suggs.push((ex.span, Sugg::hir(cx, inner, "..").to_string()));
+ (
"you don't need to add `&` to both the expression and the patterns",
- |db| {
- let inner = Sugg::hir(cx, inner, "..");
- let template = match_template(expr.span, source, &inner);
- db.span_suggestion(expr.span, "try", template);
- },
- );
+ "try",
+ )
} else {
- span_lint_and_then(
+ suggs.push((ex.span, Sugg::hir(cx, ex, "..").deref().to_string()));
+ (
+ "you don't need to add `&` to all patterns",
+ "instead of prefixing all patterns with `&`, you can dereference the expression",
+ )
+ };
+
+ suggs.extend(arms.iter().flat_map(|a| &a.pats).filter_map(|p| {
+ if let PatKind::Ref(ref refp, _) = p.node {
+ Some((p.span, snippet(cx, refp.span, "..").to_string()))
+ } else {
+ None
+ }
+ }));
+
+ span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |db| {
+ multispan_sugg(db, msg.to_owned(), suggs);
+ });
+ }
+}
+
+fn check_match_as_ref(cx: &LateContext, ex: &Expr, arms: &[Arm], expr: &Expr) {
+ if arms.len() == 2 &&
+ arms[0].pats.len() == 1 && arms[0].guard.is_none() &&
+ arms[1].pats.len() == 1 && arms[1].guard.is_none() {
+ let arm_ref: Option<BindingAnnotation> = if is_none_arm(&arms[0]) {
+ is_ref_some_arm(&arms[1])
+ } else if is_none_arm(&arms[1]) {
+ is_ref_some_arm(&arms[0])
+ } else {
+ None
+ };
+ if let Some(rb) = arm_ref {
+ let suggestion = if rb == BindingAnnotation::Ref { "as_ref" } else { "as_mut" };
+ span_lint_and_sugg(
cx,
- MATCH_REF_PATS,
+ MATCH_AS_REF,
expr.span,
- "you don't need to add `&` to all patterns",
- |db| {
- let ex = Sugg::hir(cx, ex, "..");
- let template = match_template(expr.span, source, &ex.deref());
- db.span_suggestion(
- expr.span,
- "instead of prefixing all patterns with `&`, you can dereference the expression",
- template,
- );
- },
- );
+ &format!("use {}() instead", suggestion),
+ "try this",
+ format!("{}.{}()", snippet(cx, ex.span, "_"), suggestion)
+ )
}
}
}
fn all_ranges<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
arms: &'tcx [Arm],
- id: NodeId,
-) -> Vec<SpannedRange<&'tcx ty::Const<'tcx>>> {
- let parent_item = cx.tcx.hir.get_parent(id);
- let parent_def_id = cx.tcx.hir.local_def_id(parent_item);
- let substs = Substs::identity_for_item(cx.tcx, parent_def_id);
- let constcx = ConstContext::new(cx.tcx, cx.param_env.and(substs), cx.tables);
+) -> Vec<SpannedRange<Constant>> {
arms.iter()
.flat_map(|arm| {
if let Arm {
} else {
[].iter()
}.filter_map(|pat| {
- if_chain! {
- if let PatKind::Range(ref lhs, ref rhs, ref range_end) = pat.node;
- if let Ok(lhs) = constcx.eval(lhs);
- if let Ok(rhs) = constcx.eval(rhs);
- then {
- let rhs = match *range_end {
- RangeEnd::Included => Bound::Included(rhs),
- RangeEnd::Excluded => Bound::Excluded(rhs),
- };
- return Some(SpannedRange { span: pat.span, node: (lhs, rhs) });
- }
+ if let PatKind::Range(ref lhs, ref rhs, ref range_end) = pat.node {
+ let lhs = constant(cx, cx.tables, lhs)?.0;
+ let rhs = constant(cx, cx.tables, rhs)?.0;
+ let rhs = match *range_end {
+ RangeEnd::Included => Bound::Included(rhs),
+ RangeEnd::Excluded => Bound::Excluded(rhs),
+ };
+ return Some(SpannedRange { span: pat.span, node: (lhs, rhs) });
}
- if_chain! {
- if let PatKind::Lit(ref value) = pat.node;
- if let Ok(value) = constcx.eval(value);
- then {
- return Some(SpannedRange { span: pat.span, node: (value, Bound::Included(value)) });
- }
+ if let PatKind::Lit(ref value) = pat.node {
+ let value = constant(cx, cx.tables, value)?.0;
+ return Some(SpannedRange { span: pat.span, node: (value.clone(), Bound::Included(value)) });
}
None
pub node: (T, Bound<T>),
}
-type TypedRanges = Vec<SpannedRange<ConstInt>>;
+type TypedRanges = Vec<SpannedRange<u128>>;
/// Get all `Int` ranges or all `Uint` ranges. Mixed types are an error anyway
/// and other types than
/// `Uint` and `Int` probably don't make sense.
-fn type_ranges(ranges: &[SpannedRange<&ty::Const>]) -> TypedRanges {
+fn type_ranges(ranges: &[SpannedRange<Constant>]) -> TypedRanges {
ranges
.iter()
.filter_map(|range| match range.node {
(
- &ty::Const {
- val: ConstVal::Integral(start),
- ..
- },
- Bound::Included(&ty::Const {
- val: ConstVal::Integral(end),
- ..
- }),
+ Constant::Int(start),
+ Bound::Included(Constant::Int(end)),
) => Some(SpannedRange {
span: range.span,
node: (start, Bound::Included(end)),
}),
(
- &ty::Const {
- val: ConstVal::Integral(start),
- ..
- },
- Bound::Excluded(&ty::Const {
- val: ConstVal::Integral(end),
- ..
- }),
+ Constant::Int(start),
+ Bound::Excluded(Constant::Int(end)),
) => Some(SpannedRange {
span: range.span,
node: (start, Bound::Excluded(end)),
}),
(
- &ty::Const {
- val: ConstVal::Integral(start),
- ..
- },
+ Constant::Int(start),
Bound::Unbounded,
) => Some(SpannedRange {
span: range.span,
fn is_unit_expr(expr: &Expr) -> bool {
match expr.node {
ExprTup(ref v) if v.is_empty() => true,
- ExprBlock(ref b) if b.stmts.is_empty() && b.expr.is_none() => true,
+ ExprBlock(ref b, _) if b.stmts.is_empty() && b.expr.is_none() => true,
_ => false,
}
}
+// Checks if arm has the form `None => None`
+fn is_none_arm(arm: &Arm) -> bool {
+ match arm.pats[0].node {
+ PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => true,
+ _ => false,
+ }
+}
+
+// Checks if arm has the form `Some(ref v) => Some(v)` (checks for `ref` and `ref mut`)
+fn is_ref_some_arm(arm: &Arm) -> Option<BindingAnnotation> {
+ if_chain! {
+ if let PatKind::TupleStruct(ref path, ref pats, _) = arm.pats[0].node;
+ if pats.len() == 1 && match_qpath(path, &paths::OPTION_SOME);
+ if let PatKind::Binding(rb, _, ref ident, _) = pats[0].node;
+ if rb == BindingAnnotation::Ref || rb == BindingAnnotation::RefMut;
+ if let ExprCall(ref e, ref args) = remove_blocks(&arm.body).node;
+ if let ExprPath(ref some_path) = e.node;
+ if match_qpath(some_path, &paths::OPTION_SOME) && args.len() == 1;
+ if let ExprPath(ref qpath) = args[0].node;
+ if let &QPath::Resolved(_, ref path2) = qpath;
+ if path2.segments.len() == 1 && ident.node == path2.segments[0].name;
+ then {
+ return Some(rb)
+ }
+ }
+ None
+}
+
fn has_only_ref_pats(arms: &[Arm]) -> bool {
let mapped = arms.iter()
.flat_map(|a| &a.pats)
mapped.map_or(false, |v| v.iter().any(|el| *el))
}
-fn match_template(span: Span, source: MatchSource, expr: &Sugg) -> String {
- match source {
- MatchSource::Normal => format!("match {} {{ .. }}", expr),
- MatchSource::IfLetDesugar { .. } => format!("if let .. = {} {{ .. }}", expr),
- MatchSource::WhileLetDesugar => format!("while let .. = {} {{ .. }}", expr),
- MatchSource::ForLoopDesugar => span_bug!(span, "for loop desugared to match with &-patterns!"),
- MatchSource::TryDesugar => span_bug!(span, "`?` operator desugared to match with &-patterns!"),
- }
-}
-
pub fn overlapping<T>(ranges: &[SpannedRange<T>]) -> Option<(&SpannedRange<T>, &SpannedRange<T>)>
where
T: Copy + Ord,
projects / rust.git / blobdiff